/*
    Copyright (C) 2015 Stephen Caudle

    Licensed under the Apache License, Version 2.0 (the "License");
    you may not use this file except in compliance with the License.
    You may obtain a copy of the License at

        http://www.apache.org/licenses/LICENSE-2.0

    Unless required by applicable law or agreed to in writing, software
    distributed under the License is distributed on an "AS IS" BASIS,
    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    See the License for the specific language governing permissions and
    limitations under the License.
*/

/**
 * @file    NRF51822/spi_lld.h
 * @brief   NRF51822 low level SPI driver header.
 *
 * @addtogroup SPI
 * @{
 */

#ifndef _SPI_LLD_H_
#define _SPI_LLD_H_

#if HAL_USE_SPI || defined(__DOXYGEN__)

/*===========================================================================*/
/* Driver constants.                                                         */
/*===========================================================================*/

/*===========================================================================*/
/* Driver pre-compile time settings.                                         */
/*===========================================================================*/

/**
 * @brief   SPI0 interrupt priority level setting.
 */
#if !defined(NRF51_SPI_SPI0_IRQ_PRIORITY) || defined(__DOXYGEN__)
#define NRF51_SPI_SPI0_IRQ_PRIORITY    10
#endif

/**
 * @brief   SPI1 interrupt priority level setting.
 */
#if !defined(NRF51_SPI_SPI1_IRQ_PRIORITY) || defined(__DOXYGEN__)
#define NRF51_SPI_SPI1_IRQ_PRIORITY    10
#endif

/**
 * @brief   Overflow error hook.
 * @details The default action is to stop the system.
 */
#if !defined(NRF51_SPI_SPI_ERROR_HOOK) || defined(__DOXYGEN__)
#define NRF51_SPI_SPI_ERROR_HOOK()    chSysHalt()
#endif

/*===========================================================================*/
/* Derived constants and error checks.                                       */
/*===========================================================================*/

#if !NRF51_SPI_USE_SPI0 && !NRF51_SPI_USE_SPI1
#error "SPI driver activated but no SPI peripheral assigned"
#endif

/*===========================================================================*/
/* Driver data structures and types.                                         */
/*===========================================================================*/

/**
 * @brief   Type of a structure representing an SPI driver.
 */
typedef struct SPIDriver SPIDriver;

/**
 * @brief   SPI notification callback type.
 *
 * @param[in] spip      pointer to the @p SPIDriver object triggering the
 *                      callback
 */
typedef void (*spicallback_t)(SPIDriver *spip);

/**
 * @brief   SPI frequency
 */
typedef enum {
  NRF51_SPI_FREQ_125KBPS = (SPI_FREQUENCY_FREQUENCY_K125 << SPI_FREQUENCY_FREQUENCY_Pos),
  NRF51_SPI_FREQ_250KBPS = (SPI_FREQUENCY_FREQUENCY_K250 << SPI_FREQUENCY_FREQUENCY_Pos),
  NRF51_SPI_FREQ_500KBPS = (SPI_FREQUENCY_FREQUENCY_K500 << SPI_FREQUENCY_FREQUENCY_Pos),
  NRF51_SPI_FREQ_1MBPS = (SPI_FREQUENCY_FREQUENCY_M1 << SPI_FREQUENCY_FREQUENCY_Pos),
  NRF51_SPI_FREQ_2MBPS = (SPI_FREQUENCY_FREQUENCY_M2 << SPI_FREQUENCY_FREQUENCY_Pos),
  NRF51_SPI_FREQ_4MBPS = (SPI_FREQUENCY_FREQUENCY_M4 << SPI_FREQUENCY_FREQUENCY_Pos),
  NRF51_SPI_FREQ_8MBPS = (SPI_FREQUENCY_FREQUENCY_M8 << SPI_FREQUENCY_FREQUENCY_Pos),
} spifreq_t;

/**
 * @brief   Driver configuration structure.
 */
typedef struct {
  /**
   * @brief Operation complete callback or @p NULL.
   */
  spicallback_t         end_cb;
  /**
   * @brief The frequency of the SPI peripheral
   */
  spifreq_t             freq;
  /**
   * @brief The SCK pad
   */
  uint16_t              sckpad;
  /**
   * @brief The MOSI pad
   */
  uint16_t              mosipad;
  /**
   * @brief The MOSI pad
   */
  uint16_t              misopad;
  /* End of the mandatory fields.*/
  /**
   * @brief The chip select line pad number.
   */
  uint16_t              sspad;
  /**
   * @brief Shift out least significant bit first
   */
  uint8_t               lsbfirst;
  /**
   * @brief SPI mode
   */
  uint8_t               mode;
} SPIConfig;

/**
 * @brief   Structure representing a SPI driver.
 */
struct SPIDriver {
  /**
   * @brief Driver state.
   */
  spistate_t            state;
  /**
   * @brief Current configuration data.
   */
  const SPIConfig       *config;
#if SPI_USE_WAIT || defined(__DOXYGEN__)
  /**
   * @brief Waiting thread.
   */
  thread_reference_t    thread;
#endif /* SPI_USE_WAIT */
#if SPI_USE_MUTUAL_EXCLUSION || defined(__DOXYGEN__)
#if CH_CFG_USE_MUTEXES || defined(__DOXYGEN__)
  /**
   * @brief Mutex protecting the bus.
   */
  mutex_t               mutex;
#elif CH_CFG_USE_SEMAPHORES
  semaphore_t           semaphore;
#endif
#endif /* SPI_USE_MUTUAL_EXCLUSION */
#if defined(SPI_DRIVER_EXT_FIELDS)
  SPI_DRIVER_EXT_FIELDS
#endif
  /* End of the mandatory fields.*/
  /**
   * @brief Pointer to the SPI port.
   */
  NRF_SPI_Type          *port;
  /**
   * @brief Number of bytes yet to be received.
   */
  uint32_t              rxcnt;
  /**
   * @brief Receive pointer or @p NULL.
   */
  void                  *rxptr;
  /**
   * @brief Number of bytes yet to be transmitted.
   */
  uint32_t              txcnt;
  /**
   * @brief Transmit pointer or @p NULL.
   */
  const void            *txptr;
};

/*===========================================================================*/
/* Driver macros.                                                            */
/*===========================================================================*/

/*===========================================================================*/
/* External declarations.                                                    */
/*===========================================================================*/

#if NRF51_SPI_USE_SPI0 && !defined(__DOXYGEN__)
extern SPIDriver SPID1;
#endif
#if NRF51_SPI_USE_SPI1 && !defined(__DOXYGEN__)
extern SPIDriver SPID2;
#endif

#ifdef __cplusplus
extern "C" {
#endif
  void spi_lld_init(void);
  void spi_lld_start(SPIDriver *spip);
  void spi_lld_stop(SPIDriver *spip);
  void spi_lld_select(SPIDriver *spip);
  void spi_lld_unselect(SPIDriver *spip);
  void spi_lld_ignore(SPIDriver *spip, size_t n);
  void spi_lld_exchange(SPIDriver *spip, size_t n,
                        const void *txbuf, void *rxbuf);
  void spi_lld_send(SPIDriver *spip, size_t n, const void *txbuf);
  void spi_lld_receive(SPIDriver *spip, size_t n, void *rxbuf);
  uint16_t spi_lld_polled_exchange(SPIDriver *spip, uint16_t frame);
#ifdef __cplusplus
}
#endif

#endif /* HAL_USE_SPI */

#endif /* _SPI_LLD_H_ */

/** @} */
